Many lighting systems utilize a light source such as a bulb that emits light through 360.degree. around the light source in conjunction with a reflector that may be specially designed to optimize photometric performance so that light is emitted from the lighting system through only a certain desired angle around the light source. It is well-known to further limit the angle through which light can be emitted from the light source by blocking a certain portion of that angle with devices such as louvers. The use of numerous louvers, however, tends to reduce photometric performance of the lighting system, since louvers are not at optimum positions for the particular lighting systems.
For certain types of lighting systems, such as the area or street light that directs light substantially in one direction as disclosed in U.S. Pat. No. 4,261,028 to Adam, it has been found to be useful to provide removable louvers so that the amount of light blocked by the louvers can be adapted for the specific application at hand. This arrangement is, however, relatively inflexible and does not always permit optimal performance, particularly where a lighting system ordinarily shines light over a wide area, as with a floodlight system, and the same lighting system must be adapted to various specific circumstances. It is, therefore, desirable to provide a lighting system having adjustable louvers wherein optimal adjustment of the louvers is possible.
Certain lighting systems, such as floodlight systems, are mounted on poles or other objects in the outdoors and tend to be subjected to high winds. The mounting of the lighting systems must be sufficiently strong to prevent the lighting systems from being blown away. Accordingly, the drag on the lighting systems is an important consideration in the design of lighting systems. Typical louvered lighting systems, such as that disclosed in the abovementioned Adam patent, provide the louvers on the outside of the lighting system where they tend to add to drag on the lighting system, thus limiting the size of the system both in terms of size of an individual lighting fixture and in terms of the number of lighting fixtures that can be mounted on a single mounting device, such as a pole. It is, therefore, desirable to limit the amount of drag in a lighting system.
In accordance with one aspect of the present invention, a lighting system includes a lighting fixture having an opening, the opening being defined by the edges of a wall. The lighting system also includes one or more louvers, each louver including a louver body having a first and a second end and means for gripping the edges of the wall disposed at the first and second ends of the louver body to suspend the louver body across the opening, the gripping means being slidably movable to different points along the edges of the wall.
In accordance with another aspect of the present invention, a louver for a lighting system includes a louver body having first and second ends, and C-shaped clip members disposed at each of the first and second ends.
In accordance with still another aspect of the present invention, a method for making a lighting fixture is disclosed. According to the method, a lighting fixture having a wall having an opening therein is provided, the opening being defined by edges of the wall. A louver is attached across the opening. The louver includes a louver body having a first and a second end and means for gripping the edges of the wall disposed at the first and second ends of the louver body, the gripping means permitting sliding movement of the first and second ends louver from one position on the edges of the wall to another.